Some say 50 should be the upper limit. Some say 95. Others say that human rights should come before considerations of age. The debate was sparked again this week when a 67-year-old Romanian woman, Adriana Iliescu, became the world's oldest mother, giving birth to a girl at the Giulesti maternity hospital in Bucharest.

Adriana Iliescu started her fertility treatment nine years ago, at the age of 58, and finally conceived last May. The unnamed baby was delivered by caesarean section after a twin embryo died in the womb.

"Pregnancy for a woman of that age is a potentially hazardous adventure," says Richard Kennedy, obstetrics and gynaecology consultant at University hospital, Coventry.

"When women go through menopause, their heart problems increase. When you're pregnant, you increase the workload on your heart by 40-50%. You put extra burden on the heart. That's a physiological fact.' he adds. "Fifty should be the upper age limit for childbirth because that's the time for natural menopause. Any doctor who advises women otherwise would be unprofessional and wrong."

Some people think the age limit should be even lower. The Human Fertilisation and Embryology Authority's guidelines put the maximum age for receiving an egg donation at 35.

And some think it should be higher. "I think 95 would probably be the age limit for childbirth," says fertility expert Robert Winston. "It's definitely a good thing that older women are giving birth. It can only be good for their health that all these hormones are running around," he adds.

Some disagree with an upper age limit, while recognising the health risks involved. "In the 60s, health risks do become much higher," says Dr Gillian Lockwood, medical director of Midlands Fertility Services.

"But I am not happy to have arbitrary decisions made on ageist terms. We have to take human rights into account. Instead of arguing for an upper age limit, we should look at the individual circumstances. Welfare of the child and motivations and circumstances of the mother are the most important."

And that's what concerns many. "We should look at this from the child's wishes and needs, not just the mother's," says Cristina Odone, former editor of the Catholic Herald, who had her daughter at the age of 42. "It is unnatural to give birth beyond a certain age. Even a natural birth doesn't mean it's natural."